Carlos Chastre

Since the 1980’s, several buildings throughout the world have been subject to gas explosions, impact by cars or airplanes, or car bomb attacks. In many cases the effect of the impact or explosion has been the failure of a critical structural member at the perimeter of the building. After the failure, the load supported by that member could not be redistributed and part or all of the structure has collapsed in a progressive manner. The phenomenon that occurs when local failure is not confined to the area of initial distress, and spreads horizontally and/or vertically through the structure, is termed progressive collapse.

Progressive collapse is a relatively rare event, as it requires both an accidental action to cause local damage and a structure that lacks adequate continuity, ductility, and redundancy to prevent the spread of damage. It is technically very difficult and economically prohibitive to design buildings for absolute safety. However it is possible to construct precast concrete buildings that afford an acceptable degree of safety with regard to accidental actions.

A structure is normally designed to respond properly, without damage, under normal load conditions, but local and/or global damages cannot be avoided under the effect of an unexpected, but moderate degree of accidental overload. Properly designed and constructed structures usually possess reasonable probability not to collapse catastrophically under such loads, depending on different factors, for example: the type of loading; the degree and the location of accidental loading in regard to the structure and its structural members; the type of structural system, the construction technology, and the spans between structural vertical members, etc.

No structure can be expected to be totally resistant to actions arising from an unexpected and extreme cause, but it should not be damaged to an extent that is disproportionate to the original cause.

The aim of fib Bulletin 63 is to summarize the present knowledge on the subject and to provide guidance for the design of precast structures against progressive collapse. This is addressed in terms of (a) the classification of the actions, (b) their effect on the structural types, (c) the strategies to cope with such actions, (d) the design methods and (e) some typical detailing, all supplemented with illustrations from around the world, and some model calculations.

In 1994 fib Commission 6: Prefabrication edited a successful Planning and Design Handbook that ran to approximately 45,000 copies and was published in Spanish and German.Nearly 20 years later Bulletin 74 brings that first publication up to date. It offers a synthesis of the latest structural design knowledge about precast building structures against the background of 21st century technological innovations in materials, production and construction. With it, we hope to help architects and engineers achieve a full understanding of precast concrete building structures, the possibilities they offer and their specific design philosophy. It was principally written for non-seismic structures.

The handbook contains eleven chapters, each dealing with a specific aspect of precast building structures.
The first chapter of the handbook highlights best practice opportunities that will enable architects, design engineers and contractors to work together towards finding efficient solutions, which is something unique to precast concrete buildings.
The second chapter offers basic design recommendations that take into account the possibilities, restrictions and advantages of precast concrete, along with its detailing, manufacture, transport, erection and serviceability stages.
Chapter three describes the precast solutions for the most common types of buildings such as offices, sports stadiums, residential buildings, hotels, industrial warehouses and car parks. Different application possibilities are explored to teach us which types of precast units are commonly used in all those situations.
Chapter four covers the basic design principles and systems related to stability. Precast concrete structures should be designed according to a specific stability concept, unlike cast in-situ structures.
Chapter five discusses structural connections.
Chapters six to nine address the four most commonly used systems or subsystems of precast concrete in buildings, namely, portal and skeletal structures, wall-frame structures, floor and roof structures and architectural concrete facades.
In chapter ten the design and detailing of a number of specific construction details in precast elements are discussed, for example, supports, corbels, openings and cutouts in the units, special features related to the detailing of the reinforcement, and so forth.
Chapter eleven gives guidelines for the fire design of precast concrete structures. The handbook concludes with a list of references to good literature on precast concrete construction.

TThis chapter concerns the need to evaluate the reliability of structural elements produced with recycled aggregates concrete (RAC) in order to address some designers’ scepticism towards the use of this eco-friendly material. The current knowledge on RAC’s behaviour demonstrates its viability for structural purposes. However, of the investigations performed so far very few are related to a fundamental aspect towards RAC world-wide application as a structural material: structural codes have a probabilistic basis.After briefly presenting the state-of-the-art knowledge on the material properties and structural behaviour of RAC, the limitations of the current knowledge are debated. Afterwards, an introduction to structural codification is presented, as well as the fundamentals of reliability analysis. Examples of code verifications are contextualized with their underlying assumptions and the information necessary for code calibration is discussed. The role of reliability in the calibration of structural codes is shown, common techniques for reliability calculations are briefly explained, and relevant references in the area are cited for the readers’ perusal.Having established how structural codes are calibrated, the state-of-the-art on the probabilistic and statistical knowledge of RAC properties is reviewed. The implications of the very reduced number of studies on this area are discussed and the need to conduct further studies is emphasized.Afterwards, investigations that used reliability analysis to calibrate partial safety factors applicable to RAC are reviewed. The methodology of each investigation is presented, the experimental tests that led to the definition of the probabilistic information of the RAC’s parameters are described and the need to have a wide range of data coming from different RAC compositions and aggregate sources is debated.This chapter finishes by contextualizing the current knowledge on RAC properties with the necessary information for code calibration procedures. The relevance of a code proposal towards RAC affirmation as a structural material is highlighted, as well as the requirements of such code. Suggestions for future studies are made.

Este livro apresenta diferentes perspetivas sobre o património arquitetónico em Espanha e Itália, debruçando-se sobre temas que estão na ordem do dia, como a reabilitação do património arquitetónico ou as acessibilidades ao mesmo, sejam elas na forma física ou digital, sendo os autores profundos conhecedores desta área. Nas intervenções a realizar no património edificado é fundamental ter um conhecimento aprofundado do projeto, da história e do processo construtivo da obra, bem como do seu comportamento estrutural. De acordo com o ICOMOS estas intervenções devem ser realizadas utilizando as técnicas mais adequadas, baseadas num diagnóstico apropriado e na compreensão dos materiais existentes. De igual forma, os estudos no edificado monumental devem ser realizados com o menor grau de intrusão e o máximo respeito pela sua integridade física, seguindo os princípios de salvaguarda do património arquitetónico definidos na carta internacional de Atenas.O livro divide‐se em duas grandes áreas: numa, abordam‐se os assuntos que se enquadram essencialmente no âmbito da conservação e reabilitação do património arquitetónico e na outra são apresentados os temas mais dedicados à acessibilidade do público ao património arquitetónico e à sua divulgação online. Os trabalhos apresentados no âmbito da conservação e reabilitação do património arquitetónico seguem na essência as recomendações do ICOMOS em relação à necessidade de compreensão da construção existente, ao desenvolvimento de novas técnicas e dos materiais mais adequados aos trabalhos de conservação e reabilitação, assim como na realização de testes em modelos experimentais à escala, tendo por objetivo avaliar o comportamento da estrutura antes e após a reabilitação. O património arquitetónico construído constitui uma parte importante da história da civilização humana e é um fator determinante da nossa identidade coletiva que importa preservar para as gerações futuras. Com a sua intervenção na conservação, reabilitação, valorização e divulgação do património construído, os autores deste livro estão a cumprir um importante papel na nossa sociedade, preservando um legado que nos foi deixado pelos nossos antepassados.

The 2nd International Conference on Building Materials and Materials Engineering (ICBMM 2018) was held at the University of Lisbon, Portugal, from 26 to 28 September, 2018. The objective of the Lisbon conference was to provide a platform for researchers, engineers, academics, as well as industrial professionals from all over the world, to present their research results and development activities in Building Materials and Materials Engineering.ICBMM 2018 was an opportunity for researchers, engineers and academics to further develop Building Materials and Materials Engineering. Attendees benefitted a lot from expert practitioners and researchers who presented the latest trends in theoretical and practical domains of Building Materials and Materials Engineering. Distinguished professors also delivered their keynote speeches on the latest developments in their respective fields. Among the keynote and plenary speakers were Prof. Carlos Chastre from NOVA University of Lisbon, Portugal; Prof. Paulo Mendonça from University of Minho, Portugal; Dr. Mascarenhas Mateus from University of Lisbon, Portugal; Prof. Rudolf Hela from Brno University of Technology, Czech Republic.The current set of conference proceedings present a selection of papers submitted by researchers from a variety of universities, research institutes and industries. All papers were peer-reviewed by conference committee members and a panel of international reviewers who selected the papers to be published based on their quality and relevance to the topic of the conference. This volume presents recent advances in the field of Materials Science and Engineering, Materials Properties, Measuring Methods and Applications, Materials Manufacturing and Processing, Civil and Structural Engineering, Architecture and Urban Planning.We would like to thank all the authors who have contributed to this volume and also the organizing committee, reviewers, speakers, co-chair persons, sponsors and all the conference participantsfor their strong support to ICBMM 2018, making this conference such a great success. We look forward to meeting you in ICBMM 2019!

Os edifícios históricos como os palácios, castelos, igrejas e templos, são exemplos do património construído e constituem uma parte importante do nosso património cultural. Estas construções históricas incluem normalmente paredes de alvenaria maciça e pedra natural. A salvaguarda do património construído em pedra é de importância inquestionável, pelo que devem ser desenvolvidas e estudadas técnicas de intervenção adequadas em materiais e estruturas. Neste artigo, é apresentada uma metodologia de ensaios não destrutivos para avaliar a conservação de edifícios históricos de pedra e, com base nesta metodologia, é mostrado um caso de estudo na Igreja de São Leonardo, monumento português construído na Atouguia da Baleia no século XIII.

The aim of the present communication is to present an analysis of the gravity load influence on the hysteretic behaviour of a beam-column connection. For this purpose, in the experimental campaign a new procedure for RC cyclic tests is presented in order to reproduce closer demands on the beam critical zone than the traditional procedures. The Experimental campaign included cyclic tests of the specimens according with the ECCS recommendation and an innovate procedure. The test results are presented, compared and analysed. A numerical simulation of the tests is presented where the model for the hysteretic response of the beam was calibrated with the experimental results. Finally, the behaviour of a portal frame system under cyclic displacements up to a drift of 3.5% was analysed, assuming that the non-linearity is concentrated on the plastic hinges, considering different levels of gravity load. Thus it is intended to assess the influence of the gravity load on the behaviour of a structure subjected to cyclic loads.

The façades of St. Leonard’s church and the castle in Atouguia da Baleia village in western region of Portugal are monuments built in Middle Ages. Significant stone degradation patterns are visible, being the alveolization an outstanding case study.The more porous type of sandstones similar to the variety found in the vernacular architecture of Atouguia da Baleia was treated with ethyl silicates. In order to allow the study of the durability of these conservation treatments, accelerated artificial ageing salt crystallization tests were carried out and an automatic ageing chamber was developed.Physical and mechanical behaviour was assessed on consolidated specimens before and after accelerated artificial ageing salt crystallization tests. The authors propose a prediction of the durability of these consolidation treatments by means of the salt crystallization ageing results.

Desde que o reforço estrutural começou a utilizar materiais de matriz polimérica reforçada com fibras (FRP) que o fenómeno do descolamento prematuro dos compósitos de FRP da superfície colada tem merecido especial atenção de vários autores. O conhecimento do processo de descolamento completo da ligação CFRP/betão ganhou assim, algum destaque nos últimos anos. Na generalidade, as ligações CFRP/betão têm sido analisadas com recurso métodos analíticos e numéricos sendo que, nos primeiros, se tem vindo a adoptar leis de aderência muito simplificadas das observadas experimentalmente. Apesar das simplificações adoptas nas análises analíticas, as expressões obtidas são muito importantes já que têm grande potencial em serem adoptadas pelos códigos ou normas nacionais e/ou interncionais. Por outro lado, e apesar de adoptarem leis de aderência mais refinadas, as análises numéricas permitem apenas a obtenção de expressões empíricas que podem não contemplar a generalidade dos casos estudados. Neste sentido, este trabalho apresenta um conjunto de soluções analíticas com base numa lei de aderência exponencial capaz de representar todas as não-linearidades envolvidas no descolamento da ligação CFRP/betão. Os resultados analíticos são confrontados com ensaios experimentais em que a técnica de colagem EBR foi utilizada. Contudo, o modelo analítico proposto pode ser também utilizado quando a técnica Near Surface Mounted (NSM) é adoptada. Adicionalmente, são apresentadas soluções analíticas para o caso em que o deslocamento relativo entre o CFRP e o betão é restringido por, e.g., um dispositivo de amarração mecânica instalado na extremidade oposta à aplicação de carga.